NERVES OF TOUCH. 9 



It appears probable, however, that these are not 

 really the organs of touch, but rather, perhaps, guards 

 or protectors of the true and very sensitive organs 

 within. They are, no doubt, most numerous on the 

 more sensitive parts of the skin, such as the hands and 

 tongue, and the sense of touch is most acute where they 

 occur; but they appear to be absent in some places 

 where the sense of touch certainly exists, and they 

 are abundant again in the foot, which, though not 

 especially sensitive, is particularly exposed. 



The sensation of pressure is intimately associated 

 with the hairs, which no doubt serve, at any rate in 

 some cases, for protection, but which, in Blix's * opinion 

 are in man probably all organs of touch. 



We have still indeed much to learn as to the 

 terminations of the nerves in the skin. It would seem 

 that some are connected with cells, while others termi- 

 nate in a free point. Merkel has suggested that those 

 which end in cells are the true nerves of touch, while 

 the free nerves record changes of temperature. Others, 

 perhaps with more probability, have supposed that the 

 free nerves convey merely a general and undifferen- 

 tiated sensation, while those which terminate in cells 

 give the specific impressions of pressure, heat, cold, 

 etc., any one of which may be intensified into pain. 



However, this may be, Blix * and, shortly afterwards, 

 Goldschneider t have made the interesting discovery 

 that we do not feel changes of pressure and of 



* " Exper. Beitr. zur Losung der Frage iiber die Specif. Energie der 

 Hautnerven," Zeit. fiir Biologic, 1 885. Blix's previous papers in Upsala 

 Ldkan-forenings Forhandlingar, 1882, I have not seen. 



t " Monatschr. fiir prakt. Dermatologie." 1884. " Neue Thatsachen 

 ii. die Hauptsinnesnerven," Zool. Anz., 1885 und 1886. 



